Make completion for debugindex<tab><tab> show debugindexdot, too. The special handling for commands with names that are substrings of other commands (e.g. with st and strip) wasn't used with debug commands before.

#!/bin/sh

hg init rep
cd rep
mkdir dir
touch foo dir/bar
hg -v addremove
hg -v commit -m "add 1" -d "1000000 0"
cd dir/
touch ../foo_2 bar_2
hg -v addremove
hg -v commit -m "add 2" -d "1000000 0"